The terminology and descriptions contained herein are principally from within the art field, and for those skilled in the art of, human and veterinary medicine. As such, only brief explanations of known subject matter within this art field will be provided because the details will be well known to those skilled in this art. The present invention, however, will be thoroughly described.
When two bone segments are desired to be fused, one known technique to accomplish this is to cause the two opposing bone surfaces to bleed, place and maintain them in contact with each other, and prevent them from moving for a period of time in order to allow them to fuse together.
In certain instances, two bones are desired to be fused with the aid of an implant that only penetrates the bone surfaces that are meant to contact each other and fuse together. Surgical correction of a condition called hammertoe is an example of such an instance. Of course, there are many others.
There are various known implants available for attempting to join bone surfaces together in such fashion in order for them to fuse. Some of these are monolithic implants with various barbs and arrowheads on their ends. These implants have several shortcomings. One shortcoming is that in the case of hammertoe surgery, after the bones of the joint are prepared for fusion, the joint often needs to be undesirably over-distracted in order to get the monolithic implant into both of the adjoining bone surfaces that are to be fused. This characteristic is well known to those skilled in the art. Another shortcoming of such a monolithic implant is that while it offers a measure of stability between the bone segments into which it is implanted, it provides no compressive forces to the opposing bony surfaces to assure that they stay in contact with each other until they fuse. If there is inadequate contact, fusion will not occur.
Other known implants have multiple components to them. These, too, have various shortcomings. For example, such multi-component implants are often cumbersome to implant, thus taking up valuable operating time. Additionally, to the extent that such implants are capable of providing compression, these implants do so by undesirably penetrating through additional bone surfaces other than the ones to be fused, thus causing more trauma to the patient. Moreover, some components of such implants then actually remain outside of the bones after implantation. This is undesirable because it may lead to unsightly and palpable protuberances at the surgical site after healing.
The present invention encompasses implants, and related methods, that can be quickly and easily implanted without the need for distraction, let alone over-distraction, without penetrating other bone surfaces except the two surfaces to be fused, and that, after implantation, provide for continuous compression of the two bony surfaces to be fused. The present invention is contemplated to be implanted with or without the use of guidewires. Furthermore, the present invention provides for easier implantation because of a reduced need for exactness while placing each component of an implant of the present invention into each bone segment to be fused.
The present invention is envisioned to be used with any bone surfaces that are desired to be joined. For example, an implant contemplated by the present invention can be used to fuse a single bone that has fractured or been separated, such as a femur, radius, rib, mandible or sternum. Additionally, it can be used to fuse two separate bone segments that have been prepared for fusion, such as the bones of a joint. For example, the invention may be used in the correction of a condition called Hammertoe where the bones that form the proximal, distal or interphalangeal joint of the great toe will be fused together. Bones of other joints, such as those of the hand, for example, may be similarly fused together.